| 摘要 |
A zigzag route of making a mistake and then correcting it is practiced in the present in the major route of integrated route of steel production. Impurities (sulfur, metallic residue) containing Coke is produced and when this is charged into blast furnace an impure inferior product is produced. Gases and charge are processed counter current in the blast furnace creating large blown out material requiring recovering and agglomeration it ,sintering plant. Next two processes namely BOF and Ladle processing are to rectify the previous mistake of iron making and steelmaking. Steel is cast in large size ingots and blooms having internal and external defects so surface scarfing and reheating and size reduction, scale disposing is done until the product becomes appropriate for next operation of rolling. Lot of cutting and re-joining is done producing defective portions. The rolling operation is done in air and then storing in air. The rusted surface has to be prepared by annealing and pickling for next operation of coating. Pickling creates deep defects and non uniformity in steel structure. Cold rolling is liable to produce micro-cracks in the internal structure of metal. Against this back ground in the presence process steel is produced using high purity gases and iron ore: steel is produced directly .Unwanted ingredients in iron ore are slaged off. Alloying elements when desired are added some as ores and some after steel is formed in blast furnace. Energy is recovered from liquid steel and it is directly made into appropriate temperature and dimension to perform next operation. Near net size products are produced which are given on line heat treatment in controlled atmosphere. The steel is brought in to air after required surface protection has been performed. On line heat-treatment eliminates the cold rolling. Intermediate cutting is seldom performed where there is need of certain relaxation between two operation closed atmospheres accumulators are provided, |
